MILWAUKEE — How low can beermakers go? Having conquered the beer-belly set, some of the nation's biggest brewers are trying to win over the six-pack-ab crowd with ultra-low-calorie suds.

The question is: Are drinkers willing to sacrifice flavor and a bit of the buzz? And: How long before beer gets turned back into water?

Most regular American beers, such as Budweiser, have about 150 calories and 5 percent alcohol, while most light beers contain around 100 calories and 4 percent alcohol.

The new brews, MillerCoors' Miller Genuine Draft 64 and Anheuser-Busch InBev's Select 55, are well below that. Their calorie counts are in their names, and they both contain less than 3 percent alcohol. Guzzling a whole MGD 64 or Select 55 is like taking a few swigs of a Bud.

Mindy Rotellini, a 25-year-old graphic designer from St. Louis who watches her calories, reaches for MGD 64 from time to time, even though the brew is "kind of watery" and it's tough to feel the alcohol.

"I just have to drink more, and then it's going to equal the amount of calories in a regular beer, so why not just drink a regular beer?" she says.

Chris Bethel switched to Select 55 because it is low-cal. He says he likes the light taste and doesn't mind the reduced alcohol. "I'm not a college kid trying to get wasted," says the 36-year-old network engineer in the Columbus, Ohio, area.

Both drinkers speak to an unavoidable trade-off: To cut calories, beer companies reduce the amount of malted barley and other grains that are fermented during the brewing process. That, in turn, reduces the amount of alcohol in the brew. The result is a beer more like its main ingredient, water.

"You start producing something that could taste very, very thin," says Thomas Shellhammer, professor of fermentation science at Oregon State University. "That would be the challenge for the brewer, to produce something that still tastes like beer."

(As for nonalcoholic beers, some have more flavor than others, but overall they tend to have more calories than the super-low-cal brews. The top-selling brand, O'Doul's, made by Anheuser-Busch, has about 70 calories and is thin-tasting.)

Light beers account for about half of the $99 billion-a-year beer market in the U.S., according to the Beverage Information Group, a market research firm. But the market for super-low-calorie is probably small, says Eric Schmidt, manager of information services.

MillerCoors says MGD 64 (slogan: "As light as it gets") has sold twice as much in its first year as Miller Genuine Draft Light, which it replaced a year ago. It would not release specific figures.

After a few weeks of testing Select 55 in 15 markets, Anheuser-Busch decided to expand into a dozen more starting this month. The company isn't sure yet whether demand for the beer is big enough for it to go national.

MGD 64 is 2.8 percent alcohol. Select 55 is 2.4 percent.

David Mitchell has been drinking MGD 64 since its release and says he prefers its taste to that of Coors Light, his previous beer of choice. "It's almost like drinking a glass of water, but it has the beer taste," says the 41-year-old from Gilbert, Ariz.

But some hard-core dieters aren't interested.

Beer connoisseur John LeMasney used to review craft beers on his site Beercritic.wordpress.com but gave that up after gaining 50 pounds in a year. He has cut back on his drinking to lose weight. But he refuses to try the new low-cal beers.

"I'd rather spend 200 calories and get something I really enjoy," he says.